363-206-305
Technical Specifications
10-16
Issue 3 June 2000
§ Optical path penalty includes effects of dispersion, reflection, and jitter that
occur on the optical path.
¶ One connector (0.75 dB) on each end is assumed to connect station cable
to outside plant.
∗∗
Unallocated margin, or safety margin, is typically specified from 0 dB to 3 dB.
†† Budget available for both station and transmission cable and splices.
‡‡ Attenuation and dispersion can be the limiting factors in span length. For OC-
3 single-mode fiber systems, dispersion is not a factor and all applications
are attenuation limited. The limits must be calculated based on both factors
and the lesser of the two defines the actual maximum span length. A rough
rule of thumb for attenuation-limited systems is 0.45 dB/km. This estimate
includes typical cable loss (0.4 dB/km) and splice loss (0.2 dB per splice, 11
total splices) associated with single-mode fiber.
Maximum span length can be calculated more precisely based on particular
fiber and splice characteristics and local engineering rules.
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